1. Field of the Invention
This disclosure relates to an optical head, an optical print head, an image formation apparatus, and an image reader each including a lens array.
2. Description of Related Art
Materials for lenses include an optical glass and a resin. The optical glass has a high weather resistance and excellent mechanical characteristics, but requires more complicated manufacturing processes and at a higher cost than the resin lens. Accordingly, the resin lens which is easier to process at a lower cost is preferred to be used depending on the usage purposes.
However, the dimensions of the resin lens easily change depending on a change in the environment conditions (such as temperature and humidity), and the refractive index distribution in the lens tends to change. Accordingly, an image plane distance is changed due to a change in the environment conditions to easily cause a deterioration in the optical performance, such as causing a defocus. There is a possibility that the use of such lenses in an optical print head of an image formation apparatus may cause a deterioration in the printing quality.
For example, in the field of optical pickup apparatuses, a technique has been proposed of providing a correction lens movable in an optical axis direction in order to suppress deterioration in the optical performance of lenses (for example, see Patent Literature 1).
[Patent Literature 1] Japanese Patent Application Publication No. 2011-034673 (see FIG. 1, paragraphs 0156 to 0158).